The makers of camera app Camera+ have put together a great comparison of the new iPhone 6 camera vs almost all previous generation iPhones including the first iPhone, the iPhone 3G, 3GS, 4, 4S, 5, and 5S.
Skin tones look brighter and more true to life with the iPhone 6 in this portrait series. Although the iPhone 6 photo has a higher level of detail, I’m finding it slightly pixelated and blotchy-looking. Apple altered their local tone-mapping algorithm for better exposure and contrast using the new A8 processor, but it looks like it might be causing some issues with the skin tones in these shots. Additionally, their new noise reduction algorithm seems a bit heavy handed causing pixelation.
The full comparison on the company’s site lets you view full-sized shots for a number of different shooting scenarios including daylight, backlit, macro, lowlight, and portrait shots. Here’s an example from the portrait comparison (click below for full size):